Re: [Qemu-devel] [SeaBIOS] [PATCH] acpi: hide 64-bit PCI hole for Windows XP

[Gerd Hoffmann]

  Hi,

> If we make it a rule that PCI is`setup before ACPI tables
> are read, then QEMU can do the patching itself when
> it detects BIOS reading the tables.

Approach makes sense to me.  The ordering constrain shouldn't be a big
burden, hardware detection+bringup (including pci setup) is the first
thing done by the firmware, loading/generating acpi tables is one of the
last things.  And it avoids the need to communicate the addresses (or
patch locations) between qemu+firmware.

What do you want to use this for?  pmbase and xbar are simple, they are
just a single register read.  pci io windows needs a root bus scan, but
should be doable too.

> Gerd, Laszlo,others,  does this rule work for alternative firmwares?

It surely works for coreboot, and I would be very surprised if this
causes trouble for ovmf.

cheers,
  Gerd